Re: [TLS] DSA should die

David Benjamin <davidben@chromium.org> Wed, 01 April 2015 19:53 UTC

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From: David Benjamin <davidben@chromium.org>
Date: Wed, 01 Apr 2015 19:53:18 +0000
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Subject: Re: [TLS] DSA should die
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DSA has also been removed from Chrome, so that's two major browsers.
(Chrome/Android saw it gone in October and Chrome/Windows last month.)
There's been a couple reports of servers using self-signed DSA certs for
some reason, but otherwise nothing. Before that, usage was in the noise.
Seems a safe thing to prune.

David

On Wed, Apr 1, 2015 at 2:12 PM Hanno Böck <hanno@hboeck.de> wrote:

> Hi,
>
> Mozilla just removed DSA support from Firefox. It seems the use of
> (non-ecc) DSA in TLS is pretty much nonexistent. Still the TLS 1.3 draft
> contains DSA.
>
> Proposal: DSA should go away and not be part of TLS 1.3.
>
> Reasons to remove DSA:
> * DSA with 1024 bit is considered weak and DSA with more than 1024 bit
>   is widely unsupported.
> * DSA has comparable security to RSA (it using same keysize) which is
>   the de-facto-default. Given that everybody uses RSA and nobody uses
>   DSA having the latter only adds unneccessary complexity.
> * DSA can fail badly with bad random number generators.
>
> Some numbers:
> In the 2013 https ecosystem scan there were 17 DSA keys on public IPs,
> none of them CA-trusted:
> http://conferences.sigcomm.org/imc/2013/papers/imc257-durumericAemb.pdf
>
> I think it's safe to say nobody will care if DSA is removed.
>
> cu,
> --
> Hanno Böck
> http://hboeck.de/
>
> mail/jabber: hanno@hboeck.de
> GPG: BBB51E42
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